Evaluation of Increasing Dietary Concentrations of a Multi-Enzyme Complex in Feedlot Lambs' Rations

The objective of this study was to evaluate the effects of increasing levels of the M-E complex (xylanase, glucanase, cellulase, and invertase) Optimax E® on the performance of growing lambs, their digestibility, and their rumen microbiota, and to estimate NEm, NEg, and ruminal methane levels. Forty lambs (Katahdin x Dorset; 22.91 ± 4.16 kg) were randomly assigned to dietary concentrations of ME (0, 0.2, 0.4, and 0.8% DM) and fed individually for 77 days. Increasing M-E improved feed conversion (p < 0.05) as well as NEm and NEg (p < 0.05), which were associated with increased in vivo DM and NDF digestion (linear and quadratic p < 0.01). Few microbial families showed abundancy changes (Erysipelotrichaceae, Christensenellaceae, Lentisphaerae, and Clostridial Family XIII); however, the dominant phylum Bacteroidetes was linearly reduced, while Firmicutes increased (p < 0.01), resulting in a greater Firmicutes-to-Bacteroidetes ratio. Total Entodinium showed a quadratic response (p < 0.10), increasing its abundancy as the enzyme dose was augmented. The daily emission intensity of methane (per kg of DMI or AGD) was reduced linearly (p < 0.01). In conclusion, adding the M-E complex Optimax E® to growing lambs' diets improves their productive performance by acting synergistically with the rumen microbiota, modifying the Firmicutes-to-Bacteroidetes ratio toward more efficient fermentation, and shows the potential to reduce the intensity of greenhouse gas emissions from lambs.

A Polyherbal Mixture with Nutraceutical Properties for Ruminants: A Meta-Analysis and Review of BioCholine Powder

BioCholine Powder is a polyherbal feed additive composed of Achyrantes aspera, Trachyspermum ammi, Azadirachta indica, and Citrullus colocynthis. The objective of this study was to analyze published results that support the hypothesis that the polyherbal product BioCholine Powder has rumen bypass choline metabolites through a meta-analysis and effect size analysis (ES). Using Scopus, Web of Science, ScienceDirect, PubMed, and university dissertation databases, a systematic search was conducted for experiments published in scientific documents that evaluated the effects of BioCholine supplementation on the variables of interest. The analyzed data were extracted from twenty-one publications (fifteen scientific articles, three abstracts, and three graduate dissertations available in institutional libraries). The studies included lamb growing-finishing, lactating ewes and goats, calves, and dairy cows. The effects of BioCholine were analyzed using random effects statistical models to compare the weighted mean difference (WMD) between BioCholine-supplemented ruminants and controls (no BioCholine). Heterogeneity was explored, and three subgroup analyses were performed for doses [(4 (or 5 g/d), 8 (10 g/d)], supplementation in gestating and lactating ewes (pre- and postpartum supplementation), and blood metabolites by species and physiological state (lactating goats, calves, lambs, ewes). Supplementation with BioCholine in sheep increased the average daily lamb gain (p < 0.05), final body weight (p < 0.01), and daily milk yield (p < 0.05) without effects on intake or feed conversion. Milk yield was improved in small ruminants with BioCholine prepartum supplementation (p < 0.10). BioCholine supplementation decreased blood urea (p < 0.01) and increased levels of the liver enzymes alanine transaminase (ALT; p < 0.10) and albumin (p < 0.001). BioCholine doses over 8 g/d increased blood glucose, albumin (p < 0.10), cholesterol, total protein, and globulin (p < 0.05). The ES values of BioCholine in retained energy over the control in growing lambs were +7.15% NEm (p < 0.10) and +9.25% NEg (p < 0.10). In conclusion, adding BioCholine Powder to domestic ruminants' diets improves productive performance, blood metabolite indicators of protein metabolism, and liver health, showing its nutraceutical properties where phosphatidylcholine prevails as an alternative that can meet the choline requirements in ruminants.

Meta-analysis of flavonoids use into beef and dairy cattle diet: Performance, antioxidant status, ruminal fermentation, meat quality, and milk composition

The objective of this study was to evaluate the effects of dietary supplementation with flavonoids (FLAs) on animal performance, diet digestibility, antioxidant status in blood serum, rumen parameters, meat quality, and milk composition in beef and dairy cattle through a meta-analysis. Thirty-six peer-reviewed publications were included in the data set. The weighted mean differences (WMD) between the FLAs treatments and the control treatment were used to assess the effect size. Dietary supplementation with FLAs decreased feed conversion ratio (WMD = -0.340 kg/kg; p = 0.050) and increased (p < 0.05) dry matter intake (WMD = 0.191 kg/d), dry matter digestibility (WMD = 15.283 g/kg of DM), and daily weight gain (WMD = 0.061 kg/d). In blood serum, FLAs supplementation decreased the serum concentration of malondialdehyde (WMD = -0.779 nmol/mL; p < 0.001) and increased (p < 0.01) the serum concentration of superoxide dismutase (WMD = 8.516 U/mL), glutathione peroxidase (WMD = 12.400 U/mL) and total antioxidant capacity (WMD = 0.771 U/mL). A higher ruminal propionate concentration (WMD = 0.926 mol/100 mol; p = 008) was observed in response to FLAs supplementation. In meat, the dietary inclusion of FLAs decreased (p < 0.05) shear force (WMD = -1.018 kgf/cm²), malondialdehyde content (WMD = -0.080 mg/kg of meat), and yellowness (WMD = -0.460). Supplementation with FLAs decreased milk somatic cell count (WMD = -0.251 × 103 cells/mL; p < 0.001) and increased (p < 0.01) milk production (WMD = 1.348 kg/d), milk protein content (WMD = 0.080/100 g) and milk fat content (WMD = 0.142/100 g). In conclusion, dietary supplementation with FLAs improves animal performance and nutrient digestibility in cattle. In addition, FLAs improve the antioxidant status in blood serum and the quality of meat and milk.

Effects of a Polyherbal Dietary Additive on Performance, Dietary Energetics, Carcass Traits, and Blood Metabolites of Finishing Lambs

The objective of this study was to evaluate the effects of dietary supplementation of a polyherbal additive (PA) containing hydrolyzable tannins, flavonoids, and essential oils on productive performance, dietary energetics, carcass and meat characteristics, and blood metabolites of lambs in their finishing phase. Twenty-eight Pelibuey × Katahdin lambs (20.52 ± 0.88 kg body weight (BW)) were housed in individual pens and assigned to four treatments (n = 7) with different doses of PA: 0 (CON), 1 (PA1), 2 (PA2), and 3 (PA3) g of PA kg−1 of DM for 56 days. Compared to the CON, lambs in PA1 treatment had higher average daily gain (p = 0.03), higher dietary energy utilization (p = 0.01), greater backfat thickness (p = 0.02), greater Longissimus dorsi muscle area (p = 0.01), and better feed conversion ratio (p = 0.02). PA supplementation did not affect (p > 0.05) dry matter intake, carcass yield, biometric measures, and meat chemical composition. All hematological and most of the blood biochemical parameters were similar in lambs of all treatments (p > 0.05). However, compared to the CON, lambs assigned to the PA3 treatment had lower serum urea concentration (p = 0.05) and higher serum albumin concentration (p = 0.03). In conclusion, low doses of PA could be used as a growth promoter in finishing lambs without affecting dry matter intake, carcass yield, meat chemical composition, and health status of the lambs. However, more in vivo research is needed to better understand the impact of bioactive compounds from PA used on productivity, metabolism, and health status of finishing lambs.

Impacto económico y productivo de una mezcla herbal con derivados de colina en la producción de conejos

El uso, así como el efecto productivo y económico de compuestos herbales en producción cunícola ha sido poco estudiado, por tal motivo el objetivo fue evaluar el efecto de una mezcla poliherbal rica en conjugados de colina a base de Trachyspermum ammi, Achyranthes aspera, Azadirachta indica y Citrullus colocynthis, sobre la respuesta económica y productiva de conejos para carne. Para lo cual se utilizaron 40 conejos Nueva Zelanda X California (30 días de edad), los cuales fueron aleatorizados en cinco grupos (0.0, 200, 400, 600 y 800 mg kg-1 de MS poliherbal, BioCholina®), el experimento tuvo una duración de 34 días. Se evaluó la respuesta productiva, calidad de la carne e indicadores económicos. Se utilizó un diseño completamente al azar con un arreglo de polinomios ortogonales para determinar efectos lineales y cuadráticos, con un nivel de significancia de P<0.05. Los resultados en cuanto a los parámetros productivos fueron similares entre tratamientos, excepto consumo de alimento (P=0.006) y conversión alimenticia (P=0.005) con un efecto linealmente a mayor concentración del poliherbal. La inclusión del poliherbal incrementó pH en carne (lineal, P=0.004) y coordenada b* (lineal, P=0.009), se observó que el tratamiento con 200 mg presentó los mejores indicadores económicos mejorando en 9 unidades porcentuales la razón ingresos-egresos. Se concluye que la adición de mezclas poliherbales a base de conjugado de colina natural no mejoró las variables productivas, sin embargo, se marca una tendencia económica favorable con la adición de 200 mg kg-1 de MS.

Growth Performance, Meat Quality and Antioxidant Status of Sheep Supplemented with Tannins: A Meta-Analysis

The objective of this study was to evaluate the effects of dietary supplementation with tannins (TANs) on productive performance, carcass characteristics, meat quality, oxidative stability, and blood serum antioxidant capacity of sheep through a meta-analysis. Using Scopus, Web of Science, ScienceDirect, and PubMed databases, a systematic search was performed for studies published in scientific journals that investigated the effects of TANs supplementation on the variables of interest. Only studies with weaned or older sheep were included. The data analyzed were extracted from 53 peer-reviewed publications. The sheep included in the present study were between 2 and 6 months old, and between 12 and 31 kg of body weight. The effects of TANs were analyzed using random-effects statistical models to examine the standardized mean difference (SMD) between treatments with TANs and control (no TANs). Heterogeneity was explored by meta-regression and a subgroup analysis was performed for covariates that were significant. Supplementation with TANs did not affect dry matter intake, pH, color (L* and b*), Warner-Bratzler shear force, cooking loss and meat chemical composition (p > 0.05). Supplementation with TANs increased daily weight gain (SMD = 0.274, p < 0.05), total antioxidant capacity (SMD = 1.120, p < 0.001), glutathione peroxidase enzyme activity (SMD = 0.801, p < 0.001) and catalase (SMD = 0.848, p < 0.001), and decreased malondialdehyde (MDA) concentration in blood serum (SMD = -0.535, p < 0.05). Supplementation with TANs decreased feed conversion rate (SMD = -0.246, p < 0.05), and the concentration of MDA (SMD = -2.020, p < 0.001) and metmyoglobin (SMD = -0.482, p < 0.05) in meat. However, meat redness (SMD = 0.365), hot carcass yield (SMD = 0.234), cold carcass yield (SMD = 0.510), backfat thickness (SMD = 0.565) and the Longissimus dorsi muscle area (SMD = 0.413) increased in response to TANs supplementation (p < 0.05). In conclusion, the addition of tannins in sheep diets improves productive performance, antioxidant status in blood serum, oxidative stability of meat and some other characteristics related to meat and carcass quality.

Relationships among ß-hydroxybutyrate, calcium and non-esterified fatty acids in blood with milk yield losses at early lactation

The objectives were to study the associations of concentrations of β-hydroxybutyrate acid (BHBA), calcium (Ca2+), and non-esterified fatty acids (NEFA) in blood serum 7 d prepartum with losses in milk yield (MY) and metabolic dysfunctions at seven and 14 d of lactation. Three hundred and thirty-six (336) Holstein-Friesian (780 ± 36 kg BW; which had lactated more than twice) were sampled by coccygeal venipuncture, 7 d before, and 7 and 14 d after parturition. For each sample and metabolite serum concentrations were stratified in thresholds and related to MY. When BHBA levels were high 7 d before parturition and were related to MY at d-7 postpartum, it was observed that 11.00 % of the cows lost 0.370 kg d-1 of milk. In contrast, no relationship was observed between BHBA prepartum and MY on d-14 of lactation. It was not observed any association between high NEFA and low Ca2+ levels prepartum and MY. NEFA concentrations ≥ 0.5 mmol L-1 on d-7 before calving were 7.6 more susceptible for lameness incidence (P≤ 0.01), and when BHBA ≥ 0.8 mmol L-1 cows were 2.4 times more likely to develop ketosis (P≤0.05) in the first 60 d in milk. In brief, data indicate that a high proportion of cows are above the thresholds of β-hydroxybutyrate and non-esterified fatty acids, and are also deficient in calcium, when determined one week before parturition. The risk thresholds for each metabolite were not associated with the amount of milk lost at d-14 after calving.

Genetic variability and structure of an isolated population of Ambystoma altamirani, a mole salamander that lives in the mountains of one of the largest urban areas in the world

Amphibians are globally threatened by habitat loss and fragmentation; species within the order Ambystoma are not the exception, as there are 18 species of mole salamanders in México, of which 16 are endemic and all species are under some national or international status of protection. The mole salamander, Ambystoma altamirani is a microendemic species, which is distributed in central México, within the trans-Mexican volcanic belt, and is one of the most threatened species due to habitat destruction and the introduction of exotic species. Nine microsatellite markers were used to determine the genetic structure, genetic variability, effective population size, presence of bottlenecks and inbreeding coefficient of one population of A. altamirani to generate information which might help to protect and conserve this threatened species. We found two genetic subpopulations with significant level of genetic structure (F_ST = 0.005) and high levels of genetic variability (H_o = 0.883; H_e = 0.621); we also found a small population size (N_e = 8.8), the presence of historical (M = 0.486) and recent bottlenecks under IAM and TPM models, with a low, but significant coefficient of inbreeding (F_IS = -0.451). This information will help us to raise conservation strategies of this microendemic mole salamander species.

Relaciones entre calcio, ácidos grasos no esterificados, e insulina sanguínea en preparto y leche bovina perdida en el inicio de la lactancia

Introducción: El objetivo fue determinar la relación entre las concentraciones séricas de calcio (Ca2+), ácidos grasos no esterificados (AGNE) e insulina preparto con pérdidas en la producción de leche (PL) en el inicio de la lactancia.Método: Doscientas cuarenta y tres vacas Holstein-Friesian (780 ± 36 kg PV; con más de dos lactancias) fueron muestreadas por punción coccígea varias veces antes, durante y después del parto. Para cada muestreo y cada metabolito, las concentraciones séricas se estratificaron con umbrales y se relacionaron con la PL.Resultados: Cuando los niveles de Ca2+ fueron bajos 10 días antes del parto y se relacionaron con la PL a los 10 días posparto, se observó que el 77.11% de las vacas perdieron 2.20 kg de leche; mientras en el día 20, el 66.41% de las vacas perdieron 1.40 kg animal-1 día-1. Por el contrario, cuando los AGNE fueron altos 10 días antes de parto y se relacionaron con PL, 67.40% de las vacas mostraron riesgo de perder 0.80 kg, mientras que a los 20 días posparto, el 22.00% de las vacas perdieron aproximadamente 0.90 kg vaca-1 día-1. La determinación de insulina preparto baja y PL en los días 10 y 20 de lactancia indicó que 6.02% de las vacas perdieron 0.80 y 0.70 kg de leche animal-1 día-1 para los días 10 y 20 de lactancia.Conclusión: En conclusión, niveles bajos de calcio, AGNE alto e insulina baja en sangre, obtenidos 10 días antes de parto fueron asociados con pérdidas en producción de leche en los días 10 y 20 después del parto. También se observó que los niveles bajos de calcio podrían causar mayores pérdidas de leche que los niveles altos de ácidos grasos no esterificados y las concentraciones bajas de insulina preparto. 

Genetic structure and diversity in an isolated population of an endemic mole salamander (Ambystoma rivulare Taylor, 1940) of central Mexico

Human activities are affecting the distribution of species worldwide by causing fragmentation and isolation of populations. Isolation and fragmentation lead to populations with lower genetic variability and an increased chance of inbreeding and genetic drift, which results in a loss of biological fitness over time. Studies of the genetic structure of small and isolated populations are critically important for management and conservation decisions. Ambystoma rivulare is a micro-endemic Mexican mole salamander from central Mexico. It is found in the most ecologically disturbed region in Mexico, the Trans-Mexican Volcanic Belt. The goal of this study of the population genetics of the micro-endemic mole salamander was to provide information to be used as a basis for future research and conservation planning of this species and other species of the Ambystoma genus in Mexico. The structural analysis found two subpopulations, one for each river sampled, with no signs of admixture and very high levels of genetic differentiation. Medium to high levels of heterozygosity and few alleles and genotypes were observed. Evidence of an ancestral genetic bottleneck, low values of effective population size, small inbreeding coefficients, and low gene flow were also found.

Genetic diversity and genetic structure of an endemic Mexican Dusky Rattlesnake (Crotalus triseriatus) in a highly modified agricultural landscape: implications for conservation

It is necessary to determine genetic diversity of fragmented populations in highly modified landscapes to understand how populations respond to land-use change. This information will help guide future conservation and management strategies. We conducted a population genetic study on an endemic Mexican Dusky Rattlesnake (Crotalus triseriatus) in a highly modified landscape near the Toluca metropolitan area, in order to provide crucial information for the conservation of this species. There was medium levels of genetic diversity, with a few alleles and genotypes. We identified three genetically differentiated clusters, likely as a result of different habitat cover type. We also found evidence of an ancestral genetic bottleneck and medium values of effective population size. Inbreeding coefficients were low and there was a moderate gene flow. Our results can be used as a basis for future research and C. triseriatus conservation efforts, particularly considering that the Trans-Mexican Volcanic Belt is heavily impacted by destructive land-use practices.